5.Android之image控件学习

Android中经常用到图片，比如图片浏览、图标等等，今天学习下image控件，image控件主要有ImageButton和ImageView两种。

(1)ImageButton

在布局文件增加：

<ImageButton
android:id="@+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="21dp"
android:src="@drawable/ic_launcher" />    效果：如果想改变按钮图案，可以在drawable下放自定义图标,然后修改imagebutton里面src代码即可，如图

(2)ImageView

这个稍微复杂点,但也不是很难，我们先随便添加几张图片如图：

简单修改下xml文件，

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.imagebutton.MainActivity" >
    
    <LinearLayout 
        android:id="@+id/layout1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="18dp"
        android:src="@drawable/a" />

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/spinner1"
        android:layout_below="@+id/spinner1"
        android:layout_marginTop="29dp" >
    </RadioGroup>
    
    </LinearLayout>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/layout1"
        android:layout_below="@+id/layout1"
        android:text="上一个" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button1"
        android:layout_centerHorizontal="true"
        android:text="下一个" />

</RelativeLayout>

接下来实现点击上一个或者下一个按钮，图片会发生改变功能，代码如下：

package com.example.imagebutton;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {
    
    private Button prebutton = null;
    private Button nextbutton = null;
    private ImageView imageview1 = null;
    public int i = 0;
    private int[ ] iImages = {R.drawable.a,R.drawable.b,R.drawable.c,R.drawable.d,R.drawable.e,R.drawable.f};
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        prebutton = (Button)findViewById(R.id.button1);
        nextbutton = (Button)findViewById(R.id.button2);
        imageview1 = (ImageView)findViewById(R.id.imageView1);
        prebutton.setOnClickListener(new prebuttonclick());
        nextbutton.setOnClickListener(new nextbuttonclick());    
        
        imageview1.setImageResource(i);
    }
    

    public class prebuttonclick implements OnClickListener {
        
        @Override
        public void onClick(View v) {
            if (i > 0)
            {     
                imageview1.setImageResource(iImages[--i]);
            }
            else if (i <= 0)
            {
                i = 5;
                imageview1.setImageResource(iImages[i]);
            }
        }
    }
    
    
    public class nextbuttonclick implements OnClickListener {
        @Override
        public void onClick(View v) {
            if (i < 5) 
            {
                imageview1.setImageResource(iImages[++i]);    
            }
            else if (i >= 5)
            { 
                i = 0;
                imageview1.setImageResource(iImages[i]);
            }

        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}